The present invention relates to a novel material for use as a cushion insock or in a cushion insole, which material has compression stiffness, resilience and energy absorption characteristics to provide foot comfort in conventional or sports footwear.
It has been demonstrated in a number of studies, for example as reported by T. A. McMahon and P. R. Greene in J. Biomechanics, 1986, Volume 12, pp 893-904, and by D. J. Pratt, P. H. Rees and C. Rogers, Prosthetics and Orthotics International, 1986, 10, pp 453-45 that compression stiffness and energy absorption characteristics are important in sports shoe design, in particular for designing a good running shoe. Although for a sports shoe the sole unit offers most scope for applying these principles, extra benefit can be derived from the use of an insole or insock having specifically designed compression stiffness and energy absorption characteristics. The use of insocks and insoles having specific compression stiffness and energy absorption characteristics is also desirable in conventional, non-sports footwear, where the sole unit offers less scope for modifying these characteristics.
It has been proposed to provide polymer foam-based insocks and insoles with specific compression stiffness and energy absorption characteristics but these foam-based insocks and insoles have the disadvantages that their moisture-permeability and heat-transmission and moisture-transmission properties are less advantageous than those of conventional non-woven insole and insock materials.